Abstract. Pollution from ammonia (NH3) is a widespread problem due to the effects on the environment and human health. The agricultural sector accounts for nearly all NH3 emissions in Europe; thus, focus has especially been on NH3 emissions from this sector in recent years. We need abatement techniques to reduce NH3 emissions, and in order to evaluate the techniques, there is a strong need for reliable NH3 measurement methods. Photoacoustic spectroscopy (PAS) is often used to measure NH3 concentrations, but recent discoveries show interference from compounds typically present in livestock production and during agricultural activities. We tested the performance of the Cavity Ring-Down Spectroscopy (CRDS) from Picarro for filter effects and laboratory and field calibrations with standard gasses. Furthermore, concentrations of ten volatile organic compounds (VOCs) where determined by Proton-Transfer-Reaction Mass Spectrometry (PTR-MS) to test the potential interference of these VOCs. Both laboratory and field calibrations show excellent linearity over a large dynamic range of NH3 concentrations. The analyzer shows a small humidity effect of up to a few ppb in the extreme case of a nearly water saturated air stream. Besides, from the negligible humidity dependence, there is no interference from the tested VOCs. Overall, the system performs well with only negligible influences from other compounds.

We tested the performance of the a Cavity Ring-Down Spectroscopy from Picarro to measure ammonia. Interference tests with ten volatile organic compounds (VOCs) were conducted to find potential interference of these VOCs. Calibrations show excellent linearity over a large dynamic range of NH3 concentrations. Besides, from a negligible humidity dependence, there is no interference from the tested VOCs. Overall, the CRDS system performs well with only negligible influences from other compounds.

We tested the performance of the a Cavity Ring-Down Spectroscopy from Picarro to measure ...